1. Field of the Invention
This invention relates specifically to safety and arming devices for ordnance fuzes for use on projectiles. Specifically, the invention is related to an electronic safety device for use in combination with either an electically activated mechancial arming device or electrically activated electrical arming devices. The invention is specifically related to that class of devices which utilizes the ionized gases from the propellant of the projectile in the muzzle of the firing tube as an environmental signature.
2. Description of the Prior Art
Existing mechanical safety and arming devices are limited in the number of environmental signatures usable as sources of information. The requirements now being established for modern ordnance fuzing demand additional safety and new environmental signatures.
In ordnance work, missiles and projectiles frequently employ electrical energy in their detonator trains. Conventionally, electrical energy is supplied by a battery or the like, and separate devices are employed for applying energy from the battery to the detonator train at the proper time. Means are provided to keep the missile or projectile in a safe, unarmed condition until it is desired that the missile or projectile be armed. Numerous efforts have been made to improve the simplicity and reliability of arming and detonator systems for projectiles and missiles. One result of such efforts is exemplified in the system disclosed in U.S. Pat. No. 3,098,163 to Robert W. Blis. Another related invention is exemplified in U.S. Pat. No. 3,324,317 to Gerald L. Hazelet.
Hazelet includes a supported and insulated piece of electric crystal which is subject to loading by an inertial mass in response to acceleration of the assembly employing the mass and crystal. The mass and crystal are housed together with a support in such a manner that discharge of a portion of the voltage generated in the crystal is accomplished by ionization of a gas therein; the constants being selected to provide discharge in response to a predetermined degree of acceleration. The arrangement is such that upon decrease in acceleration, electrical energy is stored in the device for use in the missile or projectile whenever desired.
Another approach to the safety and arming problem in ordnance fuzing is provided in U.S. Pat. No. 3,175,496 to Jean Rochat. In Rochat's invention the firing electric device comprises an electric generator, a part of the magnetic circuit of which is displacable under spring influence to produce the electric energy necessary to fire the projectile. This part of the magnetic circuit is maintained in position before discharge by a locking device sensitive to the acceleration of the projectile. It comprises an inertial mass displacable against the action of a spring.
It is accordingly an object of this invention to provide a new safety device which utilizes gas which escapes past a fuze as it emerges from its gun barrel.
It is therefore specifically an object of this invention to utilize the electrical charge exhibited by the plasma-like properties of the gas which accumulates above the fuze as it is fired as a new environmental signature.
Further objects and the entire scope of the invention will become more fully apparent in the following detailed description and the appended claims.